The blower comes on. When it is working I hear a click then the gas comes on. The problem is most times I can't get the gas to come on. Sometimes I can take off the cover to the heater and tap around inside and it will come on. Usually not. Gas works fine to the stove. My son had the same problem and he replaced thr regulator on his gas tank. Any thoughts? If I have to take it in for service it is $110/hour. Ouch!

Mo/re info. I just tried to run the frig on propane and I can't get that to light either. There is gas in the tank. I was told some of this stuff won't light without the proper flow of gas. I think I hear gas flowing to the frig, very slightly. Tomorrow I am replacing the regulator on the propane tank. Do you tink that will help

You will not hear much from the gas. The appliances only receive about .5 pounds of pressure.
Yes, since the other items don't work on LP then it could be the regulator. You didn't say anything about the water heater. Does it light/

I don't have a water heater. The only propane appliances are the frig, heater and stove. Now that I think about the flame on the stove seems a little low. But on the other hand maybe I am just making that up to make myself feel better. I have a gauge on the propane tank and it show full. I have the regulator off and since a new one is only $13 I will try that first.

It could also be the sail switch - tapping on the fan cover may jostle the switch enough to where it closes but your timing has to be right, it you wait too long after the blower fan starting it will think it took too long for the fan to get up to speed and not attempt to light. The other thing it could be is the fan motor, if the bearings are tight it will not spin up to full speed and therefore not close the sail switch. You can check that by turning the fan (with it off) and see if it feels tight, little "notches" when it's turning is ok, that's the magnets.

Another thing to try is to turn the bottle off. Then turn it on very slowly. You may need to do it a few times as the OPD valve assembly may think that there is a leak, but actually it is only trying to fill up the lp lines.

I read someplace about the sail switch. It seems like the fan is spinning real freely. As I look inside I see a little thing that looks like a tiny metal flag hanging down. I wonder if that is the sail switch. If the regulator doesn't pan out I will try that next. Is it a readily available part?

The sail switch should be working as it must be operated for the circuit board in most furnaces receives it's power through the sail switch.
The OPD valve is the valve inside the tanl itself. It prevents over filling the bottle. The valves also has excess flow valve in most. In the event of a ruptured line it shuts off the flow of LP. If there is insufficient back pressure in the LP system, it will stop the flow from the tank.